Low-Magnitude Earthquakes at the Eastern Ultraslow-Spreading Gakkel Ridge, Arctic Ocean

2021 ◽  
Author(s):  
Alexey Nikolaevich Morozov ◽  
Natalya V. Vaganova ◽  
Galina N. Antonovskaya ◽  
Vladimir E. Asming ◽  
Irina P. Gabsatarova ◽  
...  
Keyword(s):  
Detection Threshold ◽  
Global Network ◽  
Relative Location ◽  
Gakkel Ridge ◽  
Svalbard Archipelago ◽  
Local Seismicity ◽  
Seismic Stations ◽  
Lower Detection ◽  
Severnaya Zemlya ◽  
Over Time

Abstract Thanks to the new permanent seismic stations installed in the Franz Joseph Land and Severnaya Zemlya arctic archipelagoes, it has become possible at present to record earthquakes occurring in the eastern Gakkel ridge with a much lower detection threshold than that provided by the global network. At present, the lowest recorded magnitude is ML 2.4 and the magnitude of completeness is 3.4. We examined the results of seismic monitoring conducted from December 2016 through January 2020 to show that the earthquake epicenters are not uniformly distributed both in space and over time within the eastern part of the ridge. There were periods of quiescence and seismic activity. Most of the epicenters are confined to the area between 86° and 95.0° E. Relative location techniques were used to locate the single major swarm of earthquakes recorded so far. Most earthquakes were recorded by two or three stations only, so that relative location techniques have been able to yield reliable data for an analysis of the swarm. We showed that there have been actually two swarms that contained different numbers of events. The earthquakes in the larger swarm were occurring nonuniformly over time and clustered at certain depths. The ML scale was calibrated for the Eurasian Arctic based on records of the seismic stations installed in the Svalbard Archipelago, Franz Joseph Land, and on Severnaya Zemlya: −logA0(R)=1.5×logR100+1.0×10−4(R−100)+3.0. The results will help expand our knowledge of the tectonic and magmatic processes occurring within the ultraslow Gakkel ridge, which are reflected in the local seismicity.

scholarly journals Film Thickness-Profile Measurement Using Iterative Peak Separation Structured Illumination Microscopy

2021 ◽  
Vol 11 (7) ◽  
pp. 3023
Author(s):  
Kejun Yang ◽  
Chenhaolei Han ◽  
Jinhua Feng ◽  
Yan Tang ◽  
Zhongye Xie ◽  
...  
Keyword(s):  
Modulation Depth ◽  
Thickness Distribution ◽  
Detection Threshold ◽  
Profile Measurement ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Separation Algorithm ◽  
Peak Separation ◽  
Lower Detection ◽  
Depth Response

The surface and thickness distribution measurement for transparent film is of interest for electronics and packaging materials. Structured illumination microscopy (SIM) is a prospective technique for measuring film due to its high accuracy and efficiency. However, when the distance between adjacent layers becomes close, the peaks of the modulation depth response (MDR) start to overlap and interfere with the peak extraction, which restricts SIM development in the field of film measurement. In this paper, an iterative peak separation algorithm is creatively applied in the SIM-based technique, providing a precise peak identification even as the MDR peaks overlap and bend into one. Compared with the traditional method, the proposed method has a lower detection threshold for thickness. The experiments and theoretical analysis are elaborated to demonstrate the feasibility of the mentioned method.

The Crown Letter roundtable discussion

2020 ◽  
Vol 9 (2) ◽  
pp. 264-269
Author(s):  
Susan Barnet ◽  
Anne Brunswic ◽  
Michelle Deignan ◽  
Liza Dimbleby ◽  
Ruth Maclennan ◽  
...  
Keyword(s):  
Contemporary Art ◽  
Women Artists ◽  
Global Network ◽  
Roundtable Discussion ◽  
Over Time

Natacha Nisic recognized that the conditions of confinement created by the COVID pandemic and lockdown posed a threat to the visibility, exchange and experience of contemporary art, particularly of the work of women artists. Nisic invited women in her global network to contribute to the project and over time the network has expanded. Over 50 artists have now contributed to the publications and they maintain the online project collectively. As well as weekly publications, since the beginning The Crown Letter has hosted a weekly Salon for its contributors, where the artists exchange experiences, ideas and stories. In these times of confinement, where the effects of systemic inequality are felt across the globe, The Crown Letter harnesses the power of artistic exchange, collective energy, support and dialogue. As it approaches its first anniversary, some of the artists gathered at a salon to reflect on what The Crown Letter means to them.

scholarly journals Piezoresistive Carbon Nanofiber-Based Cilia-Inspired Flow Sensor

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 211 ◽  
Author(s):  
Debarun Sengupta ◽  
Duco Trap ◽  
Ajay Giri Prakash Kottapalli
Keyword(s):  
Carbon Nanofiber ◽  
Detection Threshold ◽  
Flow Sensor ◽  
Oxygen Intake ◽  
Mems Devices ◽  
Flow Sensors ◽  
Flow Monitoring ◽  
Flow Sensing ◽  
Artificial Cilia ◽  
Lower Detection

Evolving over millions of years, hair-like natural flow sensors called cilia, which are found in fish, crickets, spiders, and inner ear cochlea, have achieved high resolution and sensitivity in flow sensing. In the pursuit of achieving such exceptional flow sensing performance in artificial sensors, researchers in the past have attempted to mimic the material, morphological, and functional properties of biological cilia sensors, to develop MEMS-based artificial cilia flow sensors. However, the fabrication of bio-inspired artificial cilia sensors involves complex and cumbersome micromachining techniques that lay constraints on the choice of materials, and prolongs the time taken to research, design, and fabricate new and novel designs, subsequently increasing the time-to-market. In this work, we establish a novel process flow for fabricating inexpensive, yet highly sensitive, cilia-inspired flow sensors. The artificial cilia flow sensor presented here, features a cilia-inspired high-aspect-ratio titanium pillar on an electrospun carbon nanofiber (CNF) sensing membrane. Tip displacement response calibration experiments conducted on the artificial cilia flow sensor demonstrated a lower detection threshold of 50 µm. Furthermore, flow calibration experiments conducted on the sensor revealed a steady-state airflow sensitivity of 6.16 mV/(m s−1) and an oscillatory flow sensitivity of 26 mV/(m s−1), with a lower detection threshold limit of 12.1 mm/s in the case of oscillatory flows. The flow sensing calibration experiments establish the feasibility of the proposed method for developing inexpensive, yet sensitive, flow sensors; which will be useful for applications involving precise flow monitoring in microfluidic devices, precise air/oxygen intake monitoring for hypoxic patients, and other biomedical devices tailored for intravenous drip/urine flow monitoring. In addition, this work also establishes the applicability of CNFs as novel sensing elements in MEMS devices and flexible sensors.

A longitudinal, multimodal approach to characterizing chemotherapy-induced peripheral neuropathy.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e21595-e21595 ◽  
Author(s):  
Sabrina Ramnarine ◽  
Patrick M. Dougherty ◽  
Linda J Williams ◽  
Charlie Gourley ◽  
Marie T Fallon
Keyword(s):  
Peripheral Neuropathy ◽  
Upper Limb ◽  
Lower Limb ◽  
Detection Threshold ◽  
Post Treatment ◽  
Dominant Hand ◽  
Motor Score ◽  
Mechanical Detection ◽  
Grooved Pegboard Test ◽  
Over Time

e21595 Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a complex, dose-limiting toxicity impacting prognosis and quality of life. The optimal approach to identification and assessment remains unclear. This study aims to prospectively characterize the development and trajectory of CIPN using a combination of patient-reported outcomes (PROs) and objective Quantitative Sensory Testing (QST) measures in gynaecological, colorectal and lung cancer patients receiving neurotoxic platinum and/or taxane-based chemotherapy. Methods: Patients (n = 33, mean age 60.8) were evaluated at baseline prior to chemotherapy, during (every 3 weeks) and post-treatment every 3 months up to 1 year. Assessments at each time point included: PRO (EORTC QLQ-CIPN20 questionnaire) and QST measures (thermal and mechanical detection and grooved pegboard test). Statistical modelling using repeated measures analysis by patient was conducted. Results: Significant and parallel changes were observed in PROs and QST measures over time. Total EORTC score (sensory, motor and autonomic) increased in severity from baseline at all time points, peaking at 3 months post-treatment (34.8% increase; p < 0.0001) and persisting at 1 year (17.9% increase; p = 0.01). Every increase by one point in EORTC sensory score over time corresponded with an elevation in QST parameters: warm detection threshold (upper limb; p = 0.02 and lower limb; p = 0.03) and mechanical detection threshold, MDT (upper limb; p = 0.04 and lower limb; p = 0.02). Equally, rising total EORTC and motor score were related to increasing MDT in the upper limb p = 0.02 and p = 0.003 respectively. A delay of one second taken to complete the grooved pegboard test (dominant hand) was linked to a proportional increase in EORTC motor score (p = 0.01). Conclusions: Associations are shown here amongst PROs and QST parameters providing an opportunity to quantify and synthesize objective with subjective measures of neuropathy in CIPN patients. This may have potentially informative implications to underlying mechanisms of CIPN symptom burden, contributing to a more comprehensive clinical picture and allow stratification of patients by phenotype severity. Additional studies are warranted.

scholarly journals ЕARTHQUAKE NEAR CRILLON CAPE on NOVEMBER 25th, 2013 with Mw=5.2, I0=6–7 (Sakhalin Island)

2019 ◽  
pp. 466-476 ◽  
Author(s):  
E. Semenova ◽  
D. Safonov ◽  
T. Fokina
Keyword(s):  
Water Area ◽  
Sakhalin Island ◽  
Global Network ◽  
Local Network ◽  
Seismic Model ◽  
Regional Network ◽  
The South ◽  
Earthquake Parameters ◽  
Seismic Stations ◽  
Field Stations

On November 25, 2013, at 03:23 UTC, an earthquake with a magnitude of МwGCMT=5.2 was recorded in the Laperuz Strait water area. This earthquake was the strongest in the south of Sakhalin Island in 2013. Parameters of the earthquake have been determined by data of seismic stations of the regional network of GS RAS Sa-khalin branch, seismic stations of global network IRIS (GSN) and Hokkaido University. Earthquake parameters on data of regional network are in accordance with data of the international seismological centers. The intensity of concussions in some areas of Sakhalin was 4–5 points on a scale of MSK-64 and 3 points on the JMA scale on the island of Hokkaido. The focus shift has happened under conditions of close horizontal compression, seismodislocation type – uplift. The earthquake of 2013 has arisen in the place of regional tec-tonic structures contact – breaks of West Sakhalin and Central Sakhalin. The seismic model was described by data of local network of field stations. Results of observations of an earthquake on November 25, 2013 are written in this article.

scholarly journals Evaluation of the Performance Characteristics of the Lightning Imaging Sensor

2019 ◽  
Vol 36 (6) ◽  
pp. 1015-1031 ◽  
Author(s):  
Daile Zhang ◽  
Kenneth L. Cummins ◽  
Phillip Bitzer ◽  
William J. Koshak
Keyword(s):  
Detection Threshold ◽  
Tropical Rainfall Measuring Mission ◽  
Performance Characteristics ◽  
Viewing Angle ◽  
Lightning Detection ◽  
Laboratory Calibration ◽  
Lower Detection ◽  
Pixel Array ◽  
Radio Signals ◽  
Imaging Sensor

AbstractThe Lightning Imaging Sensor (LIS) that was on board the Tropical Rainfall Measuring Mission (TRMM) satellite captured optical emissions produced by lightning. In this work, we quantify and evaluate the LIS performance characteristics at both the pixel level of LIS events and contiguous clusters of events known as groups during a recent 2-yr period. Differences in the detection threshold among the four quadrants in the LIS pixel array produce small but meaningful differences in their optical characteristics. In particular, one LIS quadrant (Q1, X ≥ 64; Y ≥ 64) detects 15%–20% more lightning events than the others because of a lower detection threshold. Sensitivity decreases radially from the center of the LIS array to the edges because of sensor optics. The observed falloff behavior is larger on orbit than was measured during the prelaunch laboratory calibration and is likely linked to changes in cloud scattering pathlength with instrument viewing angle. Also, a two-season comparison with the U.S. National Lightning Detection Network (NLDN) has uncovered a 5–7-km north–south LIS location offset that changes sign because of periodic TRMM yaw maneuvers. LIS groups and flashes that had any temporally and spatially corresponding NLDN reports (i.e., NLDN reported the radio signals from the same group and/or from other groups in the same flash) tended to be spatially larger and last longer (only for flashes) than the overall population of groups/flashes.

Beaten paths towards the transnational corporate elite

2021 ◽  
pp. 026858092110516
Author(s):  
Diliara Valeeva ◽  
Frank W Takes ◽  
Eelke M Heemskerk
Keyword(s):  
Social Structure ◽  
Corporate Control ◽  
Global Network ◽  
Economic Activities ◽  
Driving Mechanisms ◽  
Corporate Elite ◽  
Novel Approach ◽  
The World ◽  
Corporate Elites ◽  
Over Time

The transnationalization of economic activities has fundamentally altered the world. One of the consequences that has intrigued scholars is the formation of a transnational corporate elite. While the literature tends to focus on the topology of the transnational board interlock network, little is known about its driving mechanisms. This article asks the question: what are the trajectories that corporate elites follow in driving the expansion of this network? To answer this, the authors employ a novel approach that models the transnationalization of elites using their board appointment sequences. The findings show that there are six transnationalization trajectories corporate elites follow to expand the network. The authors argue that while the transnational elite network appears as a global social structure, its generating mechanisms are regionally organized. This corroborates earlier findings on the fragmentation of the global network of corporate control, but also provides insights into how this network was shaped over time.

scholarly journals ALADINA – an unmanned research aircraft for observing vertical and horizontal distributions of ultrafine particles within the atmospheric boundary layer

2015 ◽  
Vol 8 (4) ◽  
pp. 1627-1639 ◽  
Author(s):  
B. Altstädter ◽  
A. Platis ◽  
B. Wehner ◽  
A. Scholtz ◽  
N. Wildmann ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Ultrafine Particles ◽  
Detection Threshold ◽  
Number Concentration ◽  
Background Information ◽  
Small Particles ◽  
Significant Difference ◽  
Lower Detection ◽  
Research Aircraft

Abstract. This paper presents the unmanned research aircraft Carolo P360 "ALADINA" (Application of Light-weight Aircraft for Detecting IN situ Aerosol) for investigating the horizontal and vertical distribution of ultrafine particles in the atmospheric boundary layer (ABL). It has a wingspan of 3.6 m, a maximum take-off weight of 25 kg and is equipped with aerosol instrumentation and meteorological sensors. A first application of the system, together with the unmanned research aircraft MASC (Multi-Purpose Airborne Carrier) of the Eberhard Karls University of Tübingen (EKUT), is described. As small payload for ALADINA, two condensation particle counters (CPC) and one optical particle counter (OPC) were miniaturised by re-arranging the vital parts and composing them in a space-saving way in the front compartment of the airframe. The CPCs are improved concerning the lower detection threshold and the response time to less than 1.3 s. Each system was characterised in the laboratory and calibrated with test aerosols. The CPCs are operated in this study with two different lower detection threshold diameters of 11 and 18 nm. The amount of ultrafine particles, which is an indicator for new particle formation, is derived from the difference in number concentrations of the two CPCs (ΔN). Turbulence and thermodynamic structure of the boundary layer are described by measurements of fast meteorological sensors that are mounted at the aircraft nose. A first demonstration of ALADINA and a feasibility study were conducted in Melpitz near Leipzig, Germany, at the Global Atmosphere Watch (GAW) station of the Leibniz Institute for Tropospheric Research (TROPOS) on 2 days in October 2013. There, various ground-based instruments are installed for long-term atmospheric monitoring. The ground-based infrastructure provides valuable additional background information to embed the flights in the continuous atmospheric context and is used for validation of the airborne results. The development of the boundary layer, derived from backscatter signals of a portable Raman lidar POLLYXT, allows a quick overview of the current vertical structure of atmospheric particles. Ground-based aerosol number concentrations are consistent with the results from flights in heights of a few metres. In addition, a direct comparison of ALADINA aerosol data and ground-based aerosol data, sampling the air at the same location for more than 1 h, shows comparable values within the range of ± 20 %. MASC was operated simultaneously with complementary flight patterns. It is equipped with the same meteorological instruments that offer the possibility to determine turbulent fluxes. Therefore, additional information about meteorological conditions was collected in the lowest part of the atmosphere. Vertical profiles up to 1000 m in altitude indicate a high variability with distinct layers of aerosol, especially for the small particles of a few nanometres in diameter on 1 particular day. The stratification was almost neutral and two significant aerosol layers were detected with total aerosol number concentrations up to 17 000 ± 3400 cm−3 between 180 and 220 m altitude and 14 000 ± 2800 cm−3 between 550 and 650 m. Apart from those layers, the aerosol distribution was well mixed and reached the total number concentration of less than 8000 ± 1600 cm−3. During another day, the distribution of the small particles in the lowermost ABL was related to the stratification, with continuously decreasing number concentrations from 16 000 ± 3200 cm−3 to a minimum of 4000 ± 800 cm−3 at the top of the inversion at 320 m. Above this, the total number concentration was rather constant. In the region of 500 to 600 m altitude, a significant difference of both CPCs was observed. This event occurred during the boundary layer development in the morning and represents a particle burst within the ABL.

scholarly journals Seismic impact of variously distant earthquakes upon the territory of Belarus

2019 ◽  
Vol 1 (1) ◽  
pp. 92-100
Author(s):  
Gennadii Aronov
Keyword(s):  
Monitoring Network ◽  
Seismic Events ◽  
Local Seismicity ◽  
Seismic Stations ◽  
Ground Shaking ◽  
The Earth ◽  
Observation Network ◽  
Wide Range ◽  
Seismic Impact ◽  
Southern Greece

The control of the geological environment is one of the most important tasks of the seismological monitoring in the territory of Belarus. The seismological monitoring in Belarus is carried out with a system of continuous round-the-clock computer-aided observations of the seismic events of natural and artificial origin in a wide range of distances and energies. The major task of the seismic environment observation network in the territory of Belarus is recording of the distant, regional, and local seismic events. Since 1966 till the present, the environmental monitoring network of the seismic stations located within the territory of Belarus recorded 60,876 seismic events in various regions of the Earth. The data obtained from strong distant, regional and local seismic events recorded by the seismic stations were analyzed, and the intensity of the seismic impact of the recorded earthquakes upon the studied territory was calculated using the N.V. Shebalin’s formula. The results of investigations performed were used to assess the seismic impact upon the territory of Belarus. A catastrophic earthquake that occurred in the Northern Sumatra western coasts in December 26, 2004, should be mentioned first among the largest earthquakes of the Earth that exerted the strongest impact upon the studied territory. An earthquake in southern Greece on January 8, 2006, and the second one in Turkey on October 23, 2011, are the events that should be mentioned among the strongest earthquakes of Europe and its adjacent areas which impact was important for the territory under study. An earthquake in Rumania on September 23, 2016, was one of the regional earthquakes that had a strong influence on the territory of Belarus. The results of the quantitative assessment of the ground shaking from earthquakes differently distant from the territory of Belarus are used for upgrading maps of the general and local seismicity, as well as for solving several other scientific and applied problems.

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